EP1280322B1 - Method of setting up an intercom communication in a local radiocommunication network - Google Patents

Description

The present invention relates to communications between telephone handsets a local radio network for transmitting digital signals.

When such a network is established according to the DECT standard for example, it includes a basic radio network through which handsets, also called terminals, can communicate between them. The base is a central node of the network, which transmits to each handset the digital, voice or data signals received from his correspondent with whom he communicates.

To process a plurality of simultaneous communications, the base slaves the handsets telephones by synchronizing them on a time frame of a plurality of channels the first of which are reserved for transmissions from the base to the handsets telephones and the latter are reserved for transmissions in the opposite direction. Such a frame is of the TDMA / TDD Multiple Access Time Division / Division type Temporal duplex. To establish this temporal enslavement, the base emits cyclically a beacon, a code word, in a predetermined transmission channel, indicating its rank in the frame. Any telephone handset that enters the coverage area base station recognizes the beacon and, according to the corresponding instant and the rank of the channel, it determines the beginning of the new frame and thus temporally transmissions and receptions on the frame of the base.

Within such a network, it is also known to establish a direct handset link telephone handset. This mode of communication allows two users to communicate without having to be within range of the DECT database.

To establish this mode of communication, the known procedure is to seize everything first a 5-digit key with a three-digit group number for identify the base and two digits to identify the handset (s) with which one wishes to communicate in this mode and which contain in memory the same group number. Once this information is pre-entered, one can put two telephone handsets in direct mode communication by selecting this mode on handsets and entering the handset number with which one wishes to put in direct communication.

The Applicant notes that in the majority of uses, the number of telephone handsets in service on a base is very small compared to the number that can be reserved, ie a hundred. Indeed if we aim
a predominantly family or single network user market, the number of handsets in use does not exceed two or three.

The Applicant has set as a general objective to reduce as much as possible the manipulations on telephone handsets.

Moreover, since the direct communication mode between handsets is very similar to the operation of walkie-talkies where you just have to press the button to enter into communication with his interlocutor, he would desirable for the users to reproduce this mode of operation on the handsets.

• établissement d'une première connection entre le premier combiné téléphonique et la base,
• transmission des informations de connection pour établir une seconde connection entre les deux combinés téléphoniques,
• établissement de la deuxième connection entre les deux combinés téléphoniques,
• transmission des données bipassant la base.

EP 1051875 discloses a method for establishing communication between a radio base and at least a first and a second telephone handset or mobile station. It includes the following steps:

• establishing a first connection between the first handset and the base,
• transmission of the connection information to establish a second connection between the two handsets,
• establishing the second connection between the two handsets,
• data transmission bypassing the base.

The Applicant has therefore set itself the particular objective of arranging the handsets telephones in order to reduce the manipulations to those required on talkies

It has achieved this with the process according to the invention of inter-handset communications in a local area network multiple division time division duplex radio communication, comprising a plurality of telephone handsets and a radio base connected to an external network to which they are associated, the telephone handsets being arranged to be able to transmit in direct mode, characterized in that at least one of the handsets telephones turns into a radio base and sends a bell-type message group when he is calling.

Thanks to the solution of the invention, once the handsets have been placed in the position of direct communication from telephone handset to telephone handset, one of the users enters into communication with his or her correspondents by pressing on the call key. At this time, the handset (s) ring and the first who "picks up" takes the communication. If the first handset telephone who has picked up is not the recipient, he hangs up, and we start the procedure.

la figure 1 représente schématiquement un réseau local de radiocommunication DECT ;

la figure 2 représente le schéma bloc fonctionnel d'un combiné téléphonique du réseau et,

la figure 3 représente un organigramme illustrant la procédure de communication.

The description which follows gives an embodiment with reference to the drawings in which

FIG. 1 schematically represents a DECT local area radio network;

FIG. 2 represents the block diagram of a handset of the network and,

Figure 3 shows a flowchart illustrating the communication procedure.

The telephone network of the figure is here a DECT network and has a radio base 1 connected to a link 10 of an external network, the switched telephone network for example. The base manages the communications of a plurality of radio terminals such as than those referenced C1 and C2, located in the radio coverage area of the base. The terminals are telephone handsets.

Figure 2 schematically shows the different functional blocks of a handset telephone C1, implemented in the context of the invention. The telephone handset conventionally comprises a radio transmission and reception block 30, an interface man-machine 39 and a central control unit 37. The radio block 30 is intended for transmit and receive data through a radio transmission channel, following the DECT protocol, in order to communicate with the base 1. The human-machine interface 39 comprises an input keyboard 31, a display screen 32, a microphone 33 and a speaker 35. The microphone 33 and the loudspeaker 35 are respectively connected to a analog / digital converter (ADC) 34 and a digital converter / 36. The typing keyboard 31 includes telephone keys standards including the key of line, a key to command the display of a main menu and keys to move in the menu tree. The block central control unit 37 comprises a microprocessor, to which all the elements of the C1 telephone handset are connected, and is arranged to control the operation handset C1.

Conventionally, the base 1 synchronizes the terminals, that is to say the slaves for stall their frames in opposition to that of the radio base, by cyclic emission on a beacon path of a synchronization message. The message specifies the rank, from 0 to 11, of the beacon path in the frame and the terminals can thus determine the future moment of the beginning of the next frame. They are thus perfectly locked in opposition of phase by relative to the frame of the radio base.

When the two terminals C1 and C2 are not within radio range of the radio base, we know establish a communication between the two terminals in this case. It's about a communication called in direct mode. Handsets feature the function direct mode. In this case, at least one of the handsets, the one that is calling, has the basic radio function.

In order to establish direct mode communication, users must prior to entering a group number from 000 to 999, the number of their handset telephone number and the telephone numbers of the correspondents between 00 and 99.

Then users must select on their handset the use in live mode, or in a drop-down menu that appears on the handset screen telephone, or on a specific key if the telephone handset has one.

When there is no communication, all handsets are then the status "Assets not synchronized". When the handsets are out of range of the radio base, no beacon signal is transmitted and the handsets scan every 10 seconds the channels in search of a signal with the identity appropriate. When a user, whose handset includes the function radio base, wants to establish a communication out of reach of the base, it specifies the handset number of the called party then presses the handset button. The calling telephone handset is transformed into a radio base. A channel is selected, and the handset starts to emit a beacon signal with the message which includes in particular the handset identification of the corresponding. All handsets receive the beacon signal but only the called telephone handset is allowed to be in the idle synchronized state. he is then waiting for communication and maintains frame and multi-frame synchronization with the radio base.

The called handset rings and the user answers. According to the DECT standard messages exchanged between the two handsets are of the type P _T (paging tail) to the short format and include the temporary identifier assigned (TPUI) of the called handset. This value is calculated from the group number and the handset number.

According to the invention, the communication procedure is simplified in direct by incorporating into the message transmitted by the beacon a group ringing function.

The procedure is then as follows; with reference to FIG.

Two or more users wishing to be able to establish a communication between them talky walky type with their handsets C1, C2, Cn must first check if they are matched to the same base. For this, they check on the drop-down menu of their handsets they have the same group number. If so, they choose a common number.

Then they select on their menu the direct mode function without identifier. All handsets are then in the logical state "active not synchronized. They regularly scan channels waiting for a beacon signal.

After a while, one of the users wishes to communicate with one of the other users. He presses the handset key on his handset telephone C1.

If C1 is in radio view of the base to which all handsets are paired, an intercommunication is then established through the radio base.

If C1 is not in radio view of the base, it turns into a radio base and sends a beacon signal on which other handsets synchronize. As they each receive the word that the ring is for the group, they all ring.
One of the users will pick up and establish communication with C1. C1 will know if C2 is the correspondent he wanted to reach. If so, the communication continues. If it does not, it asks C2 to hang up and interrupts the call. He presses the call key again. Another correspondent picks up. The procedure is repeated until the correct correspondent is found. All other handsets that are in radio range during channel scanning recognize the beacon signal and synchronize to the beacon channel.

It is certain that this procedure is of interest when there is only one corresponding. We are sure to reach it immediately when we press the green key.

Claims (5)

1. Method of establishing communication between handsets in a local radiocommunication network with time-division multiple access/duplex, comprising at least one radio base (1) connected to an external network such as the switched telephone network, and, associated with said base, a plurality of handsets (C1, Cn) of which at least one (C1) is arranged to be able to transform itself into a radio base and establish a communication in direct mode, characterised in that said handset (C1) is arranged to send in direct mode a beacon signal including a message of the group ringing type.
2. Method according to the preceding claim, the handsets (C1, Cn) not being paired to the same radio base, characterised in that it includes a stage of prior seizure of a common group number by the handsets which are to communicate in direct mode.
3. Method according to claim 1, characterised in that, when the other handsets (C2, Cn) within radio range ring, the first handset to be lifted takes the communication.
4. Method according to the preceding claim, characterised in that, if the first person (C2) to have lifted the handset is not the intended recipient, he hangs up and the process of sending said beacon signal is restarted by pressing on the seizure key.
5. Handset for implementing the method according to one of the preceding claims, arranged to be able to make itself into a radio base, characterised in that it is arranged to send a beacon signal including a message of the group ringing type.

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